Artificial photosynthesis for CO2-to-ethylene conversion enabled by dye-sensitised carbon nitrides

光电化学（PEC）电池是一种独特的装置，结合了太阳能直接转换成化学键，以及电解的紧凑性和催化可调性。光电催化是一种很有前途的解决方案，可用于大规模合成太阳能燃料，即具有可输送能量含量的化学品，以及光重整，即光驱动将废物转化为增值产品。在阴极方面，太阳能驱动的二氧化碳还原成碳氢化合物和其他有机分子是太阳能燃料合成和脱碳战略的一个有前途的场所。对于阳极反应，甘油因其易于氧化和目前作为生物柴油合成副产物的过量生产而被认为是良好的光重整底物。然而，甘油氧化通常会产生混合物，包括甘油醛和1,3-二羟基丙酮，后者更有价值。这个博士项目的目的是设计和制造一个独立的PEC装置，包括一个光电阴极，用于从二氧化碳中高速合成C2-C3碳氢化合物，以及一个光电阳极，用于在酸性环境下将甘油选择性光重整为1,3-二羟基丙酮。在铜基光电阴极中加入串联钙钛矿太阳能电池，将使二氧化碳以非常正的起始电位和破纪录的光电流转化为碳氢化合物。另一方面，不同的光吸收半导体，包括聚合碳氮化物和钙钛矿，将被筛选用于制造甘油氧化的光阳极。阳极反应的选择性将通过最先进的Pt-Bi电催化剂或底物特异性酶来实现。最后，两个电极将结合在一个独立的装置中，实现无偏置、太阳能驱动的完整氧化还原循环。

Photoelectrochemical (PEC) cells are unique devices combining direct solar light conversion into chemical bonds with the compactness and catalytic tuneability of electrolysis. Photoelectrocatalysis is a promising solution for the scalable synthesis of solar fuels, i.e. chemicals with deliverable energetic content, and photoreforming, that is the light-driven conversion of waste into added-value products. On the cathodic side, solar-driven CO2 reduction to hydrocarbons and other organic molecules is a promising venue to solar fuels synthesis and strategy for decarbonisation. For the anodic reaction, glycerol has been proposed as excellent photoreforming substrate for its facile oxidation and its current overproduction as a byproduct of the synthesis of biodiesel. However, glycerol oxidation usually leads to a mixture of products, including glyceraldehyde and 1,3-dihydroxyacetone, with the latter being more valuable. The purpose of this Ph.D. project will be to design and fabricate a stand-alone PEC device comprising a photocathode for high-rate synthesis of C2-C3 hydrocarbons from CO2 and a photoanode for the selective photoreforming of glycerol to 1,3-dihydroxyacetone in acidic environment. The incorporation of a tandem perovskite solar cell in a copper-based photocathode will enable conversion of CO2 to hydrocarbons at very positive onset potentials and record-breaking photocurrents. On the other hand, different light-absorbing semiconductors, including polymeric carbon nitrides and perovskites, will be screened for the fabrication of a photoanode for glycerol oxidation. Selectivity of the anodic reaction will be achieved either by state-of-the-art Pt-Bi electrocatalysts or substrate-specific enzymes. Finally, the two electrodes will be combined in a stand-alone device for a bias-free, solar-driven complete redox cycle.